JP7372339B2 - Battery module and its manufacturing method - Google Patents

Description

[Mutual citation with related applications]
This application claims priority benefit based on Korean Patent Application No. 10-2019-0030176 dated March 15, 2019, and all contents disclosed in the documents of the Korean patent application are hereby incorporated by reference. included.

The present invention relates to a battery module and a method of manufacturing the same, and more particularly to a battery module having a connection structure of electrode leads and bus bars, and a method of manufacturing the same.

Secondary batteries are attracting a lot of attention as an energy source in a variety of product groups such as mobile devices and electric vehicles. Such secondary batteries are a powerful energy resource that can replace the use of existing products that use fossil fuels, and are attracting attention as an environmentally friendly energy source because they do not generate byproducts due to energy use.

Recently, as the need for high-capacity secondary battery structures has increased, including the use of secondary batteries as an energy storage source, multi-module structures have been developed, in which battery modules in which a large number of secondary batteries are connected in series/parallel are assembled. Demand for battery packs is increasing.

On the other hand, when configuring a battery pack by connecting multiple battery cells in series/parallel, a battery module consisting of at least one battery cell is configured, and other components are added using such at least one battery module. A common method of constructing a battery pack is as follows.

Such a battery module includes a plurality of battery cells that are stacked on each other and a bus bar that electrically connects electrode leads of the plurality of battery cells.

FIG. 1 is a diagram illustrating electrode leads connected to bus bars in a conventional battery module.

Referring to FIG. 1, conventionally, battery cells are stacked to form a battery cell stack 40, and then the battery cell stack 40 and a busbar frame (not shown) to which the busbar 20 is attached are assembled to form a battery. Electrode leads 10 formed to protrude from the cell laminate were joined to bus bars 20 attached to the bus bar frame by laser welding or the like.

However, as shown in FIG. 1, when assembling the battery cell stack 40 with the bus bar 20, the electrode lead 10 connected to the battery cell stack 40 should be bent and joined to the bus bar. There is a problem in that a spring-back phenomenon occurs in which the bending of the electrode lead that has already been bent during the process returns to its original state due to elasticity.

Similarly, as shown in FIG. 1, when the plurality of electrode leads 10 are bent and joined to the bus bar 20 side by side, the plurality of electrode leads 10 are bent and joined to the bus bar while being overlapped. At this time, a gap occurs between the electrode leads due to the springback current interaction that occurs between the electrode leads 10 and a positional difference between the electrode leads 10 due to bending, and welding is performed according to the distance between the electrode leads 10 and the bus bar 20. Since a difference also occurs between the electrode leads 10 and the bus bar 20, the bonding strength between the electrode lead 10 and the bus bar 20 may decrease, and an abnormality may occur in electrical connectivity.

Further, the electrode lead 10 may be manually bent due to breakage of the lead or the like, which may cause problems such as a reduction in the automation process rate and a reduction in weldability quality.

The problem to be solved by the present invention is to provide a battery module having a bus bar and electrode lead connection structure that improves processability and reliability of electrical connection between the electrode leads and the bus bar, and a method for manufacturing the same. .

The problems of the present invention are not limited to the problems mentioned above, and other problems not mentioned can be clearly understood by those skilled in the art from the following description.

A battery module according to an embodiment of the present invention for achieving the above-mentioned object includes a battery cell stack in which a plurality of battery cells are stacked, an electrode lead formed to protrude from the battery cell stack, and the electrode lead and the battery cell stack. The bus bar includes a bus bar to which the bus bar is electrically connected and a bus bar frame to which the bus bar is attached, and the bus bar is formed of a sandwich part and a fixing part that connects and fixes the sandwich part, and the electrode lead is attached to the sandwich part of the bus bar. installed between.

The busbar frame may include a lower opening portion corresponding to a fixing portion of the busbar and a catch portion corresponding to an end of a sandwiching portion of the busbar.

The lower opening may correspond to a structure in which the busbar frame is depressed.

The sandwiching part of the bus bar may be formed of two clip parts extending from the fixing part, and the distance between the two clip parts may decrease toward the fixing part.

The electrode lead may contact the clip portion at a portion closer to the fixing portion than an end of the clip portion.

The electrode lead may be formed into a protruding flat plate shape.

The battery cell stack may further include cell terraces protruding from adjacent battery cells among the battery cells included in the battery cell stack, and the electrode leads may be formed to protrude from the cell terraces.

The sandwiching portion of the bus bar may be in close contact with the flat plate surface of the electrode lead in a direction perpendicular to the flat surface of the electrode lead.

A method for manufacturing a battery module according to an embodiment of the present invention includes the steps of: attaching a busbar to an opening of a busbar frame; inserting an electrode lead between the sandwich parts of the busbar; and tightly fitting the busbar and the electrode lead with a jig. and removing the jig.

In the step of bringing the bus bar and the electrode lead into close contact, the jig may be inserted between the bus bar frame and the bus bar to bring the bus bar and the electrode lead into close contact.

In the battery module according to an embodiment of the present invention, flat electrode leads are inserted and attached to the bus bars, and the electrode leads and the bus bars can be joined without bending the electrode leads. Reliability can be obtained in connection with electrical connections made by

Further, since the battery module according to the embodiment of the present invention does not require manual processes required for bending operations, it is possible to improve the automation process rate in production.

In addition, in the battery module according to an embodiment of the present invention, the bus bar and the electrode lead are brought into close contact with each other using a jig so that the electrical connection between the electrode lead and the bus bar is stably established.

In addition, in the battery module according to an embodiment of the present invention, the weight of the busbar can be reduced due to the thin clip-shaped busbar structure.

The effects of the present invention are not limited to the effects mentioned above, and other effects not mentioned can be clearly understood by those skilled in the art from the description of the claims.

FIG. 3 is a diagram illustrating electrode leads connected to bus bars in a conventional battery module. FIG. 1 is a perspective view showing a battery module according to an embodiment of the present invention. FIG. 3 is a diagram showing the electrode lead of FIG. 2 inserted into a bus bar. FIG. 4 is a sectional view of the busbar frame of FIG. 3 viewed from the front. FIG. 5 is a cross-sectional view showing a busbar and electrode leads attached to the busbar frame of FIG. 4; FIG. 6 is a cross-sectional view showing how a jig is inserted into the busbar frame of FIG. 5 to bring the busbar and the electrode lead into close contact.

It should be understood that the embodiments described below are shown as examples for better understanding of the invention, and that the present invention can be implemented with various modifications different from the embodiments described herein. However, in explaining the present invention, if it is determined that a detailed explanation of related known functions or components would unnecessarily obscure the gist of the present invention, the detailed explanation and specific illustrations will be omitted. Further, the accompanying drawings are not drawn to scale, and the sizes of some of the components may be exaggerated for better understanding of the invention.

Although the terms first and second used in this application are used to describe various components, the components are not limited by the terms. These terms are only used to distinguish one component from another.

Further, the terms used in this application are merely used to describe specific embodiments, and are not intended to limit the scope of rights. A singular expression includes a plural expression unless the context clearly indicates otherwise. In this application, the words "comprising," "consisting of," and "consisting of" refer to the presence of features, numbers, steps, acts, components, parts, or combinations thereof that are described in the specification. and shall be understood as not excluding in advance the possibility of the presence or addition of one or more other features, numbers, steps, operations, components, parts, or combinations thereof. Must be.

Hereinafter, a battery module according to an embodiment of the present invention will be described with reference to FIGS. 2 and 3. FIG.

FIG. 2 is a perspective view showing a battery module according to an embodiment of the present invention. FIG. 3 is a diagram showing the electrode lead of FIG. 2 inserted into a bus bar.

Referring to FIGS. 2 and 3, a battery module according to an embodiment of the present invention basically includes a battery cell stack in which a plurality of battery cells 100 are stacked, and battery cells 100 included in the battery cell stack. It includes a protruding electrode lead 120, a bus bar 200 that is electrically connected to the electrode lead 120, a bus bar frame 300 to which the bus bar 200 is attached, and further includes a frame member 500 that surrounds the battery cell stack and the bus bar frame 300. .

The battery cell 100 can be configured as a pouch-type secondary battery as a secondary battery. A plurality of battery cells 100 may be stacked on top of each other so as to be electrically connected to each other to form a battery cell stack.

Each of the plurality of battery cells 100 may include an electrode assembly, a battery case, and an electrode lead 120 protruding from the electrode assembly. The electrode assembly may include an anode plate, a cathode plate, a separator, and the like. The battery case is for packaging the electrode assembly, and is made of a laminate sheet including a resin layer and a metal layer. Such a battery case may include a case body and a cell terrace 110. An electrode lead 120 may be electrically connected to the electrode assembly.

The configuration of the battery cell 100 described above is an example, and the configuration of the battery cell 100 for configuring the battery cell stack can be variously modified.

The electrode lead 120 is formed of a flat plate and protrudes from at least one side of the battery cell 100 . The electrode leads 120 may be stacked and protruded in one direction, thereby allowing the electrode leads 120 to be connected in series or in parallel. The electrode lead 120 can function as a battery terminal and is made of a metal material such as copper or aluminum. Further, the electrode lead 120 may be formed with various thicknesses and widths. The thickness and width of the electrode lead 120 can be manufactured to vary depending on the specifications of the secondary battery and battery module.

The bus bar 200 may contact and be electrically connected to the electrode lead 120. The bus bar 200 is made of an electrically conductive metal material such as copper or aluminum similarly to the electrode lead 120 for electrical connection with the electrode lead 120.

Hereinafter, a busbar frame, a busbar attached to the busbar frame, and an electrode lead connected to the busbar in a battery module according to an embodiment of the present invention will be described in detail with reference to FIGS. 2 to 5.

FIG. 4 is a sectional view of the busbar frame of FIG. 3 viewed from the front. FIG. 5 is a sectional view showing the busbar and electrode leads attached to the busbar frame of FIG. 4.

Referring to FIG. 4, a busbar frame 300 according to an embodiment of the present invention has a structure in which a portion of the upper end is opened to form an opening 310. The opening 310 may include a hook 311 having a step at its upper end with reference to the entrance of the opening 310, and may include a lower opening 312 that is further depressed downward from the center of the opening 310 at its lower end.

Referring to FIG. 5, the bus bar 200 according to the present embodiment includes a sandwich part 210 into which the electrode lead 120 is inserted, and a fixing part 220 that connects and fixes the sandwich part 210.

The pinching portion 210 is formed of two clip portions 211 and 212 extending from the fixing portion 220 in the upper diagonal direction. When the electrode lead 120 is inserted, the electrode lead 120 may come into contact with the inner surfaces of the two clip parts 211 and 212.

The fixing part 220 may serve to connect and fix the sandwich part 210 below the sandwich part 210 . The fixing part 220 is connected to the lower ends of the two clip parts 211 and 212, respectively. According to an embodiment of the present invention, the fixing part 220 is formed to have a curvature on the lower side of the clip part 210, and The lead 120 facilitates the insertion of the clip 210 and elastically prevents deformation or movement of the clip 210, thereby fixing the clip 210.

The bus bar 200 as described above is attached to an opening 310 formed in a bus bar frame 300 provided on one side of the battery cell stack. At this time, the upper end of the clipping part 210 is located at the hanging part 311 of the busbar frame 300, and the fixing part 220 is located at the lower open part 312 of the busbar frame 300.

The hook portions 311 are recessed at both upper apexes of the opening 310, and the upper ends of the clip portions 211, 212 on both sides of the clip portion 210 are hooked and attached to the hook portions 311 to prevent the bus bar 200 from moving. It can be supported on the upper side.

The lower open part 312 is formed to correspond to the structure in which the bus bar frame 300 is sunk downward, and the fixing part 220 is inserted and attached to the lower part to support the bus bar 200 at the bottom so that the bus bar 200 does not move.

As a result, the busbar frame 300 can support the sandwiching portions 210 of the busbar 200 at the upper left and right sides, and can support the fixing portion 220 of the busbar at the lower center.

According to the embodiment of the present invention, the sandwiching part 210 and the fixing part 220 of the bus bar 200 are formed in the shape of a curved plate-like clip having a minimum width enough to make contact with the flat surface of the electrode lead 120. By reducing the unnecessary volume of the structure, a lighter busbar device can be attached to the battery module.

The electrode lead 120 is electrically connected to the bus bar 200, which requires contact between the electrode lead 120 and the bus bar 200. According to an embodiment of the present invention, the electrode leads 120 are stacked in a horizontal direction in a flat plate shape and are formed to protrude from each of the plurality of battery cells 100 , and the electrode leads 120 that protrude in this way are formed in the sandwiched portion of the bus bar 200 . After being inserted into the bus bar 210, it is contacted and fixed by the left and right clip parts 211, 212 to establish an electrical connection with the bus bar 200.

The upper side of the busbar frame 300 has an open structure and is formed so that the electrode lead 120 can be easily inserted into the busbar frame 300. Since the electrode lead 120 is formed to have an open side, the electrode lead 120 can be easily inserted and attached to the sandwich portion 210 of the bus bar 200 using the bus bar frame 300 and the upper open structure of the bus bar 200 .

The distance between the two clip portions 211 and 212 becomes smaller toward the lower fixing portion 220 based on the distance between the upper ends of the clip portions 211 and 212. Therefore, the electrode lead 120 inserted from above the bus bar 200 can be inserted downward along the insertion space formed by the two clip parts 211 and 212 of the sandwich part 210. The distance between portions 211 and 212 becomes smaller.

Therefore, the electrode lead 120 can contact a portion between the two clip parts 211 and 212 formed closer to the fixing part 220 than the upper end side of the two clip parts. More specifically, since the flat surface of the electrode lead 120 corresponds to the opposing surfaces of the two clip parts 211 and 212, the sandwiching part 210 of the bus bar 200 is in close contact with the flat surface of the electrode lead 120 in the vertical direction. can be contacted.

According to the embodiment, the narrower the interval between the hook parts 311 located at both upper ends of the bus bar frame 300, the narrower the interval between the two clip parts 211 and 212. The contact position between can be moved upward.

According to an embodiment of the invention, the contact between the two components is made by a welded connection in order to enable continuous contact between the electrode lead 120 and the sandwich portion 210 of the busbar 200. It will be done.

As in the embodiment of the present invention, when the electrode lead 120 is formed to protrude into a flat plate shape and is inserted and attached between a clip-shaped bus bar consisting of a sandwiching part and a fixing part, it is not necessary to bend the electrode lead 120. Since there is no spring back phenomenon due to bending, the reliability of the electrical connection between the electrode lead and the bus bar can be ensured.

FIG. 6 is a cross-sectional view showing how a jig is inserted into the busbar frame of FIG. 5 to bring the busbar and electrode lead into close contact.

Hereinafter, a method for manufacturing a battery module according to an embodiment of the present invention will be described with reference to FIGS. 2 to 6.

First, the bus bar 200 is attached onto the opening 310 of the bus bar frame 300. The clamping parts 210 of the busbar 200 are attached to catch parts 311 formed on both sides of the upper opening of the busbar frame 300, and the fixing parts 220 of the busbar 200 are attached to the lower opening of the busbar frame 300. At this time, the bus bar 200 is attached using a jig 400.

After the busbar 200 is attached to the busbar frame 300, the electrode leads 120 are inserted between the sandwich parts 210 of the busbar 200. Thereby, the electrode lead 120 is electrically connected to the bus bar 200 on both sides.

After the electrode lead 120 is inserted between the sandwich portions 210 of the bus bar 200, the bus bar 200 and the electrode lead 120 are brought into close contact with each other using a jig. As shown in FIG. 6, the jig is inserted into the space between the busbar frame 300 and the busbar 200, so that the busbar 200 and the electrode lead 120 can be brought into close contact with each other. By bringing the bus bar 200 and the electrode lead 120 into close contact with each other, reliability of the electrical connection between them can be ensured.

After the bus bar 200 and the electrode lead 120 are brought into close contact with each other using the jig 400, the jig 400 can be removed from the battery module.

Although preferred embodiments of the present invention have been illustrated and described above, the present invention is not limited to the specific embodiments described above, and without departing from the gist of the present invention claimed in the claims, the present invention is not limited to the specific embodiments described above. It goes without saying that the present invention can be modified and implemented in various ways by those having ordinary knowledge in the technical field, and such modified implementations should not be understood separately from the technical idea and outlook of the present invention.

100 Battery Cell 110 Cell Terrace 120 Electrode Lead 200 Bus Bar 210 Clipping Part 211 First Clip Part 212 Second Clip Part 220 Fixing Part 300 Bus Bar Frame 310 Opening Part 311 Hanging Part 312 Lower Open Part 400 Jig

Claims (11)

A battery cell laminate in which a plurality of battery cells are stacked,
an electrode lead formed to protrude from the battery cell laminate;
a busbar electrically connected to the electrode lead; and a busbar frame to which the busbar is attached;
The bus bar includes a sandwiching part and a fixing part that connects and fixes the sandwiching part below the sandwiching part,
The electrode lead is located between the sandwich parts of the bus bar,
The busbar frame has an opening, a catch part formed above the opening so that the upper end of the clip part is located, and a hook part formed below the opening so that the fixing part is located. and a lower opening to make the
The busbar frame and the sandwiching part each have a structure with an open upper side so that the electrode lead can be inserted between the sandwiching parts from above,
The battery module , wherein the hook portion is recessed into the opening, and an upper end of the sandwich portion is hooked on the hook portion . 2. The battery module according to claim 1, wherein the hook portion is formed with a step above the opening, and the upper end of the clip portion is attached by hooking onto the step of the hook portion. The battery module according to claim 1 or 2, wherein the lower opening is recessed below the opening, and the fixing part is inserted into and attached to the lower opening. Any one of claims 1 to 3, wherein the sandwiching part of the bus bar is formed by two clip parts extending from the fixing part, and the distance between the two clip parts becomes smaller toward the fixing part. The battery module according to item (1). The battery module according to claim 4, wherein the hook portions are formed on both sides of the opening, and upper ends of the two clip portions are attached by hooking onto the hook portions formed on both sides. The battery module according to claim 4 or 5, wherein the electrode lead contacts the clip portion at a portion closer to the fixing portion than an end portion of the clip portion. The battery module according to any one of claims 1 to 6, wherein the electrode lead is formed to protrude into a flat plate shape. The battery module according to claim 7, further comprising cell terraces protruding from adjacent battery cells among the battery cells included in the battery cell stack, and wherein the electrode leads are formed to protrude from the cell terraces. The battery module according to claim 7 or 8, wherein the sandwiching portion of the bus bar is in close contact with the flat plate surface of the electrode lead in a vertical direction. installing the busbar into the opening of the busbar frame;
inserting an electrode lead between the sandwich portions of the bus bar;
The method for manufacturing a battery module according to any one of claims 1 to 9, comprising: bringing the bus bar and the electrode lead into close contact with each other using a jig; and removing the jig. The jig brings the bus bar and the electrode lead into close contact with each other,
The method for manufacturing a battery module according to claim 10, wherein the method is inserted between the busbar frame and the busbar to bring the busbar and the electrode lead into close contact.

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